The present invention relates to an inkjet printer for outputting plotting data prepared in a host computer to paper.
Inkjet printers have been known in the art wherein an image output region corresponding to one page of the paper is divided into a plurality of bands, and the image information to be outputted is written to a bit map memory in raster data form for each band, and the image data in the bit map memory is used to control the ink discharge from nozzles of the inkjet head to output the image on long sized paper for each band.
In the preparation of the image, there is a limit to the length that the inkjet printer can plot in one operation because of a limitation coordinates to be handled in the application at the host computer side. For example, if the axis has coordinates up to 32767, in a printer with a resolution of 360 dpi, 32767.times.(25.4/360)=2311 mm is the longest length that can be handled.
Under these circumstances, a method may be used wherein the data is sectioned into certain block lengths and plotted with upper portion margin and a lower portion margin of zero, so that the next plotting is continuous with the present plotting, which effectively permits longer plotting.
In this case, as shown in FIG. 4(A), the sectioned data is regarded as data coupled with the number of nozzles of an inkjet head 14. A final image 30 of the first page (1st sheet) coincides with a discharge nozzle region D of the inkjet head 14. Accordingly, in this condition, if the paper is carried in the forward direction by a portion of width of the inkjet head 14, the band image of the second page (2nd sheet) can be made continuous with the final band image 30 of the first page with the zero margin.
However, as shown in FIG. 4(B), in case the sectioned data is not coincident with the number of nozzles of the inkjet head 14, the undischarge nozzle region X of the inkjet head 14 is not coincided with the final band image 30 on the first page. For this reason, when the plotting of the second page is to be made, where the paper is carried in the forward direction by the head width portion of the inkjet head 14, a white stripe of the undischarged nozzle region X portion is formed between the final image 30 on the first page and the first band image on the second page, which causes the discontinuation of the next plotting.
Normally, when plotting image is to be prepared at the host computer side, an operator is not required to be conscious of the number of nozzles of the plotting head of the printer. Furthermore, the application at the host computer side corresponds to a variety of printers in many cases, and since there is a possibility that the number of nozzles of the inkjet is variable among the printers, there is a problem in that the preparation of data matched with the printers is difficult.
The present invention has an object of solving the foregoing problems.